Add 100 g sabudana to a bowl along with plenty of water. Cover and soak for least five to six hours. For convenience, I usually do this overnight.
Once soaked, drain the sabudana and set aside.
Bring water to a boil in a medium-sized saucepan. Add 2 medium white potatoes, and cook until fork-tender. Drain the water and cool the potatoes, then peel the skins.
Add the potatoes to a bowl and mash thoroughly.
Dry roast (no oil) 40 g red peanuts on a tawa over high high. Cook until the skins are blistered, then turn off the heat, and use a mortar and pestle to coarsely crush them.
Add the soaked sabudana, mashed potatoes, roasted and crushed peanuts, 3 green finger chillies (chopped), 1 small handful fresh coriander (chopped), ½ teaspoon cumin seeds, ¼ teaspoon sugar, the juice of ¼ whole lime or lemon, and Himalayan rock salt (to taste) to a large bowl. Mix well.
Grease your hands with oil (to stop the mixture from sticking/getting messy!), and shape the mixture into 10-12 vada.
Add 1 litre oil to a deep fat fryer or large kadai/saucepan. Heat until it reaches around 180℃ (350℉). Once it comes to temperature, carefully lower the sabudana vada into the oil. Don't attempt to overcrowd the pan by cooking them all at once. Fry the sabudana vada for around three minutes, or until evenly golden-brown*.
Repeat the cooking process for the remaining sabudana vada. Drain on kitchen paper and serve hot.
Notes
* If you would rather not deep fry the sabudana vada, see below:
To bake sabudana vada, form the patties as per the recipe. Line a sheet pan with parchment/baking paper, and lightly brush the sago vada with oil. Bake at 220 degrees Celcius (425 degrees Fahrenheit) for around an hour, carefully turning the patties halfway through baking.
To air-fry sabudana vada, preheat your air fryer to 200 degrees Celsius (395 degrees Fahrenheit) and brush the basket with oil. Place the sabudana vada in the basket, brush the tops with more oil, then cook for 20-30 minutes or until golden. Turn them halfway through cooking.
To cook sabudana vada in an appe pan, otherwise known as an appam pan, paniyaram pan, or paniyarakkal pan, add a little oil to the pan. Shape your sabudana vada into small balls instead of patties. Once the oil is hot, place the sabudana vada balls into the pan. Cook for around 2 minutes on each side or until golden, then turn.